Re: [PATCH] Provide pid_to_exec_file on Solaris (PR tdep/17903)

[Joel Brobecker <brobecker at adacore dot com>]

Hi Rainer,

On Wed, Sep 19, 2018 at 04:17:57PM +0200, Rainer Orth wrote:
> While looking through gdb.log, I found that two tests FAIL like this:
> 
> warning: No executable has been specified and target does not support
> determining executable automatically.  Try using the "file" command.
> 0x00400dc4 in ?? ()
> (gdb) FAIL: gdb.base/attach.exp: attach2, with no file
> 
> The other is gdb.base/quit-live.exp.  I've implemented the following
> patch that fixes both failures, only then detecting that I'd previously
> reported the issue as PR tdep/17903.
> 
> Tested on amd64-pc-solaris2.10 and amd64-pc-solaris2.11, ok for master?
> 
> 	Rainer
> 
> -- 
> -----------------------------------------------------------------------------
> Rainer Orth, Center for Biotechnology, Bielefeld University
> 
> 
> 2018-06-13  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
> 
> 	PR tdep/17903
> 	* procfs.c (procfs_target): Declare pid_to_exec_file.
> 	(procfs_target::pid_to_exec_file): New.

Nice :). This is OK for me as is; one question: Have you considered
the use of an std::string for the variable "name"? I thought about it,
and I'm not sure it would make the code all that better, but thought
I'd mention it again, in case you or someone else sees something
I don't see.

> diff --git a/gdb/procfs.c b/gdb/procfs.c
> --- a/gdb/procfs.c
> +++ b/gdb/procfs.c
> @@ -128,6 +128,8 @@ public:
>  
>    const char *pid_to_str (ptid_t) override;
>  
> +  char *pid_to_exec_file (int pid) override;
> +
>    thread_control_capabilities get_thread_control_capabilities () override
>    { return tc_schedlock; }
>  
> @@ -3135,6 +3137,35 @@ procfs_target::pid_to_str (ptid_t ptid)
>    return buf;
>  }
>  
> +/* Accepts an integer PID; Returns a string representing a file that
> +   can be opened to get the symbols for the child process.  */
> +
> +char *
> +procfs_target::pid_to_exec_file (int pid)
> +{
> +  static char buf[PATH_MAX];
> +  char name[PATH_MAX];
> +
> +  /* Solaris 11 introduced /proc/<proc-id>/execname.  */
> +  xsnprintf (name, PATH_MAX, "/proc/%d/execname", pid);
> +  scoped_fd fd (open (name, O_RDONLY));
> +  if (fd.get () < 0 || read (fd.get (), buf, PATH_MAX - 1) < 0)
> +    {
> +      /* If that fails, fall back to /proc/<proc-id>/path/a.out introduced in
> +	 Solaris 10.  */
> +      ssize_t len;
> +
> +      xsnprintf (name, PATH_MAX, "/proc/%d/path/a.out", pid);
> +      len = readlink (name, buf, PATH_MAX - 1);
> +      if (len <= 0)
> +	strcpy (buf, name);
> +      else
> +	buf[len] = '\0';
> +    }
> +
> +  return buf;
> +}
> +
>  /* Insert a watchpoint.  */
>  
>  static int

-- 
Joel